Quarter	Percent
1999-01-01	28.8
1999-04-01	29.8
1999-07-01	31.7
1999-10-01	31.6
2000-01-01	31
2000-04-01	32.2
2000-07-01	33.9
2000-10-01	32.9
2001-01-01	32.8
2001-04-01	33.6
2001-07-01	35.4
2001-10-01	34.2
2002-01-01	33.8
2002-04-01	34.3
2002-07-01	35.5
2002-10-01	34
2003-01-01	33.5
2003-04-01	34.5
2003-07-01	36.2
2003-10-01	34.5
2004-01-01	34.4
2004-04-01	34.8
2004-07-01	36.8
2004-10-01	35.4
2005-01-01	36.4
2005-04-01	38.1
2005-07-01	41
2005-10-01	38.5
2006-01-01	38.1
2006-04-01	39.4
2006-07-01	41.6
2006-10-01	39.1
2007-01-01	38.2
2007-04-01	39.2
2007-07-01	41.4
2007-10-01	38.1
2008-01-01	36.6
2008-04-01	36.3
2008-07-01	38
2008-10-01	33.2
2009-01-01	29.3
2009-04-01	28
2009-07-01	28.6
2009-10-01	26.2
2010-01-01	25
2010-04-01	25
2010-07-01	26.3
2010-10-01	23.6
2011-01-01	22.1
2011-04-01	22.2
2011-07-01	23.4
2011-10-01	20.3
2012-01-01	18.6
2012-04-01	18.5
2012-07-01	19.6
2012-10-01	16.9
2013-01-01	16.3
2013-04-01	16.5
2013-07-01	18
2013-10-01	16.5
2014-01-01	15.8
2014-04-01	16.5
2014-07-01	17.6
2014-10-01	16.9
2015-01-01	16.5
2015-04-01	17.7
2015-07-01	19.6
2015-10-01	17.9
2016-01-01	17.3
2016-04-01	17.9
2016-07-01	20.0
2016-10-01	18.2
2017-01-01	18.5
2017-04-01	19.9
2017-07-01	22.9
2017-10-01	20.6
2018-01-01	19.9
2018-04-01	21.6
2018-07-01	23.5